Field of the Invention
The present disclosure generally relates to a bicycle controller and a bicycle transmission system.
Background Information
A known bicycle transmission system includes a motor that provides assistance to human power. In addition to the motor, the bicycle transmission system includes a speed reducer and a resultant force member. Rotation is transmitted to the resultant force member from the speed reducer and a crank. Japanese Patent No. 2,623,419 describes one example of a conventional bicycle transmission system.
In the conventional bicycle transmission system, the rotational speed of the motor is proportional to the rotational speed of the crank. The motor has a characteristic in which the output torque changes in accordance with its rotational speed. Depending on the rotational speed of the crank, the output torque of the motor may become insufficient and decrease the assist force or lower the motor driving efficiency.